Question

As pyruvate is completely broken down in the TCA (Krebs) cycle, some of its energy is

A) conserved in the water molecules resulting from reduction of oxygen.

B) conserved in the carbon dioxide molecules released by the processes.

C) conserved in FAD and NAD+.

D) conserved in NADH + H+ and FADH2.

E) found in the oxygen used in the electron transport chain.

Answer 1

D) conserved in NADH + H+ and FADH2.

Citric acid cycle involves a series of reactions that occur in the presence of oxygen. Citric acid cycle generates NADH, which enters into the oxidative phosphorylation process. This cycle occurs in mitochondrial matrix; it consumes 2 water molecules and generates two carbon dioxide molecules along with one ATP molecule as a direct energy source. The following are the series of reactions the occur in citric acid cycle.

The overall reaction of citric acid cycle for one acetyl CoA is,

Acetyl CoA + 3 NAD+ + FAD + GDP + Pi + 2H2O ------> 2CO2 + 3NADH + FADH2 +CoASH + GTP + 3H+.